A semiconductor device manufacturing method based on MAP is as follows: a semiconductor chip is bonded to each of plural wiring boards set on a substrate and the electrodes of the semiconductor chips are coupled (bonded) to the electrodes of the wiring boards by metal wires or a flip-chip technique and the semiconductor chips and wiring boards are collectively encapsulated with sealing resin, then the substrate and sealing resin are diced into individual wiring boards using a dicing blade. In the process of dicing the substrate to divide it into individual semiconductor devices using a dicing blade, the edge portions of the substrate become useless odd pieces since they cannot be used for semiconductor devices. For example, Japanese Unexamined Patent Publication No. Hei 11 (1999)-135557 discloses that a substrate's portions supposed to become such odd pieces are supported by supporting members.